unit 4 test prep bio

Endocytosis

The process by which cells internalize substances from their external environment by engulfing them in a membrane-bound vesicle.

Exocytosis

The process by which cells expel materials to the extracellular environment when vesicles fuse with the plasma membrane.

Phagocytosis

A type of endocytosis; the process of engulfing large particles or cells.

Fluid Mosaic Model

A model that describes the cell membrane as a flexible, dynamic structure composed of a phospholipid bilayer with embedded proteins, cholesterol, and carbohydrate chains.

Phospholipid Bilayer

The structural foundation of the cell membrane, providing a semi-permeable barrier.

Proteins in Cell Membrane

Molecules that serve as channels, carriers, receptors, or enzymes within the cell membrane.

Role of Cholesterol

Acts as a fluidity buffer in the cell membrane, stabilizing it at high temperatures and preventing tight packing at low temperatures.

Carbohydrate Chains

Chains attached to proteins or lipids in the cell membrane, important for cell recognition, adhesion, and communication.

Calvin Cycle

A light-independent reaction in photosynthesis occurring in the stroma of chloroplasts, producing glucose from CO₂.

Carbon Fixation

The initial step of the Calvin Cycle where CO₂ is converted into an organic molecule, facilitated by the enzyme RuBisCO.

Glycolysis

The metabolic process occurring in the cytoplasm that breaks down glucose into two pyruvate molecules, with a net gain of 2 ATP.

Krebs Cycle

A series of biochemical reactions in the mitochondrial matrix where Acetyl CoA is oxidized, producing NADH, FADH₂, ATP, and CO₂.

Positive Feedback Loop

A process that amplifies a change in a system, leading to further deviation from the starting condition.

Childbirth and Positive Feedback

Contractions during childbirth trigger the release of oxytocin, intensifying further contractions.

Blood Clotting

An example of positive feedback where initial clotting accelerates the process to rapidly seal a wound.

Cell Theory

A foundational principle stating that all living organisms are composed of cells, the cell is the basic unit of life, and all cells arise from pre-existing cells.

Virus Structure

The composition of a virus including genetic material (DNA or RNA), a capsid, and sometimes an envelope derived from the host cell.

Capsid

The protein coat that encases and protects the genetic material of a virus.

Lytic Cycle

A viral replication process in which the virus commandeers the host cell's machinery to rapidly produce new viral particles, culminating in cell lysis.

Lysogenic Cycle

A viral replication process where viral DNA integrates into the host genome, allowing it to replicate along with the host's DNA.

Key Difference between Lytic and Lysogenic Cycles

Lytic cycle causes immediate destruction of the host cell, whereas lysogenic cycle allows the virus to persist without destroying the host immediately.

Genetic Material in Viruses

Could be DNA or RNA, and can be single- or double-stranded.

Envelope in Viruses

A lipid membrane derived from the host cell that surrounds some viruses, often with proteins essential for infecting host cells.

Cell Membrane Fluidity

Maintained by cholesterol, allowing lateral movement of proteins and lipids within the phospholipid bilayer.

NADH in Glycolysis

A reduced form of nicotinamide adenine dinucleotide produced during glycolysis.

ATP Production in Glycolysis

Glycolysis uses 2 ATP in early stages and produces a net gain of 2 ATP.

Outputs of Krebs Cycle

Produces NADH, FADH₂, ATP (or GTP), and CO₂ as waste.

Where does pyruvate oxidation occur?

Matrix

Where does the Krebs cycle occur?

Matrix

Where does oxidative phosphorylation occur?

Inner mitochondrial membrane